Simple two train crossing/junction no path

[Rickdemption]

Hello,
unfortunately I still don't understand how signals for trains work. Played the tutorial twice, it feels like I miss one small information to understand.
Pic of my problem
http://imgur.com/a/0VJQ4
Maybe it doesn't work because my trains don't need loops to go back and forth (even though I have loops)?
Thanks for reading.

[twepy]

By placing signals at only one side of the track you made one way sections. In this topic ive written a more detailed explanation.

[Rickdemption]

Thank you twepy, I put signals on both sides and it is working now.